The Effect of Zn2+ Enrichment on the Cobalt Chromite Spinel Pigments: Synthesis, Characterization, Colorimetric and NIR Reflectance Properties

Document Type : Research Article

Authors
Hamid Reza Hedayati 1
Ali Asghar Sabbagh Alvani 2
Hassan Sameie 2
Shima Moosakhani 3
Reza Salimi 2
Farzaneh Tabatabaee 2
Ali Amiri Zarandi 3
Sajjad Kiani 3
1 Faculty of Polymer Engineering & Color Tech., Amirkabir University of Technology/Color and Polymer Research Center (CPRC), Amirkabir University of Technology
2 Color and Polymer Research Center (CPRC), Amirkabir University of Technology
3 Faculty of Polymer Engineering & Color Tech., Amirkabir University of Technology/ Color and Polymer Research Center (CPRC), Amirkabir University of Technology.
/amnc.2015.4.14.2
Abstract
In the present study, Co1-X ZnX Cr2O4  nano-pigments have been successfully synthesized via polymeric precursor method. The phase analysis was carried out by X-ray diffraction (XRD) indicating that all the samples have cubic spinel structure. SEM images showed that the grains are homogeneously individualized with a particle size of between 100-200 nm. Furthermore, UV-Vis absorption spectra exhibited an intense broad band in the range of 500-700 nm, which could be related to 4A2(F)→4T1(P)    spin-allowed electronic transition of Co2+ ions in the tetrahedral position of spinel structure. On the bedrock of colorimetric properties and UV-Vis-NIR reflectance measurements, Zn2+. enrichment of spinel structure up to 75% resulted in enhancement of chroma and green hue as well as improvement of NIR solar reflectance. High NIR reflectance properties for these pigments clearly highlights the potential for the utility of these pigments in the cool coatings.
Keywords
Near-infrared reflective pigments
Polymeric precursor method
Cool coatings
UV-Vis NIR spectrophotometry